Howard Beale, the longtime anchor of the Union Broadcasting System's UBS Evening News, learns from friend and news division president Max Schumacher that he has just two more weeks on the air because of declining ratings. The two get drunk and lament the state of their industry. The following night, Beale announces on live television that he will commit suicide on next Tuesday's broadcast. UBS fires him after this incident, but Schumacher intervenes so that Beale can have a dignified farewell. Beale promises he will apologize for his outburst, but once on the air, he launches back into a rant claiming that life is "bullshit." Beale's outburst causes the newscast's ratings to spike, and much to Schumacher's dismay, the upper echelons of UBS decide to exploit Beale's antics rather than pull him off the air. In one impassioned diatribe, Beale galvanizes the nation, persuading his viewers to shout out of their windows "I'm as mad as hell, and I'm not going to take this anymore!"

Diana Christensen heads the network's programming department; seeking just one hit show, she cuts a deal with a band of radical terrorists for a new docudrama series called The Mao Tse-Tung Hour for the upcoming fall season. When Beale's ratings seem to have topped out, Christensen approaches Schumacher and offers to help him "develop" the news show. He says no to the professional offer, but not to the personal one, and the two begin an affair. When Schumacher decides to end Beale as the "angry man" format, Christensen convinces her boss, Frank Hackett, to slot the evening news show under the entertainment division so she can develop it. Hackett agrees, bullying the UBS executives to consent and fire Schumacher. Soon afterward, Beale is hosting a new program called The Howard Beale Show, top-billed as "the mad prophet of the airwaves". Ultimately, the show becomes the most highly rated program on television, and Beale finds new celebrity preaching his angry message in front of a live studio audience that, on cue, chants Beale's signature catchphrase en masse: "We're as mad as hell, and we're not going to take this anymore." At first, Max and Diana's romance withers as the show flourishes, but in the flush of high ratings, the two ultimately find their way back together, and Schumacher leaves his wife of over 25 years for Christensen. But Christensen's fanatical devotion to her job and emotional emptiness ultimately drive Max back to try returning to his wife, even though he doesn't think she'll agree, and he warns his former lover that she will self-destruct at the pace she is running with her career. "You are television incarnate, Diana," he tells her, "indifferent to suffering, insensitive to joy. All of life is reduced to the common rubble of banality."

When Beale discovers that Communications Corporation of America (CCA), the conglomerate that owns UBS, will be bought out by an even larger Saudi Arabianconglomerate, he launches an on-screen tirade against the deal, encouraging viewers to send telegrams to the White House telling them, "I want the CCA deal stopped now!" This throws the top network brass into a state of panic because the company's debt load has made merger essential for survival. Hackett takes Beale to meet with CCA chairman Arthur Jensen, who explicates his own "corporate cosmology" to Beale, describing the interrelatedness of the participants in the international economy and the illusory nature of nationality distinctions. Jensen persuades Beale to abandon the populist messages and preach his new "evangel". However, television audiences find his new sermons on the dehumanization of society depressing, and ratings begin to slide, yet Jensen will not allow UBS executives to fire Beale. Seeing its two-for-the-price-of-one value—solving the Beale problem plus sparking a boost in season-opener ratings—Christensen, Hackett, and the other executives decide to hire the Ecumenical Liberation Army to assassinate Beale on the air. The assassination succeeds, putting an end to The Howard Beale Show and kicking off a second season of The Mao Tse-Tung Hour.

Lance Henriksen has a small uncredited role as a network lawyer at the meetings in Diana Christensen's Los Angeles office, and at Ahmet Khan's home.

Ken Kercheval makes an appearance as a lawyer in the negotiation scene.

Some sources indicate that Tim Robbins has a small, non-speaking role at the end of the film as one of the assassins who kills Beale;[5] however, Robbins has publicly stated that he did not appear in the film.[6]

Part of the inspiration for Chayefsky's script allegedly came from the on-air suicide of television news reporter Christine Chubbuck in Sarasota, Florida two years earlier.[7] The anchorwoman was suffering from depression and battles with her editors, and unable to keep going, she shot herself on camera as stunned viewers watched on July 15, 1974. Chayefsky used the incident to set up his film's focal point. As he would say later in an interview, "Television will do anything for a rating... anything!" However, Dave Itzkoff's book Mad as Hell: The Making of Network and the Fateful Vision of the Angriest Man in Movies disputes this, asserting that Chayefsky actually began writing Network months before Chubbuck's death and already planned for Howard Beale to vow to kill himself on air; Chubbuck's suicide was an eerie parallel.[8]

The character of network executive Diana Christiansen was based on NBC daytime television programming executive Lin Bolen,[9] which Bolen disputed.[10]

Chayefsky and producer Howard Gottfried had just come off a lawsuit against United Artists, challenging the studio's right to lease their previous film, The Hospital, to ABC in a package with a less successful film. Despite this recent lawsuit, Chayefsky and Gottfried signed a deal with UA to finance Network, until UA found the subject matter too controversial and backed out.

Undeterred, Chayefsky and Gottfried shopped the script around to other studios, and eventually found an interested party in Metro-Goldwyn-Mayer. Soon afterward, UA reversed itself and looked to co-finance the film with MGM, which for the past several years had handled MGM's distribution. MGM agreed to let UA back on board, and gave it the international distribution rights, with MGM controlling North American/Caribbean rights.

Network opened to acclaim from critics, and became one of the big hits of 1976–77. Vincent Canby, in his November 1976 review of the film for The New York Times, called the film "outrageous ... brilliantly, cruelly funny, a topical American comedy that confirms Paddy Chayefsky's position as a major new American satirist" and a film whose "wickedly distorted views of the way television looks, sounds, and, indeed, is, are the satirist's cardiogram of the hidden heart, not just of television but also of the society that supports it and is, in turn, supported."[11]

In a review of the film written after it received its Academy Awards, Roger Ebert called it a "supremely well-acted, intelligent film that tries for too much, that attacks not only television but also most of the other ills of the 1970s," though "what it does accomplish is done so well, is seen so sharply, is presented so unforgivingly, that Network will outlive a lot of tidier movies."[12] Seen a quarter-century later, Ebert added the film to his Great Movies list and said the film was "like prophecy. When Chayefsky created Howard Beale, could he have imagined Jerry Springer, Howard Stern, and the World Wrestling Federation?"; he credits Lumet and Chayefsky for knowing "just when to pull out all the stops."[13]

Not all reviews were positive: Pauline Kael in The New Yorker, in a review subtitled "Hot Air", criticized the film's abundance of long, preachy speeches; Chayefsky's self-righteous contempt for not only television itself but also television viewers; and the fact that almost everyone in the movie, particularly Robert Duvall, has a screaming rant: "The cast of this messianic farce takes turns yelling at us soulless masses."[14]Michael Billington wrote, "Too much of this film has the hectoring stridency of tabloid headlines",[15] while Chris Petit in Time Out described it as "slick, 'adult', self-congratulatory, and almost entirely hollow", adding that "most of the interest comes in watching such a lavishly mounted vehicle leaving the rails so spectacularly."[16]

The film ranks at number 100 in Empire magazine's list of the 500 Greatest Films of All Time.[17] On review aggregator website Rotten Tomatoes, Network currently holds a 91% "fresh" rating based on 56 reviews.[18]

Finch died before the 1977 ceremony and was the only performer to win a posthumous Academy Award until Heath Ledger won a Best Supporting Actor Oscar in 2009. The statuette itself was collected by Finch's widow, Eletha Finch.

Straight's performance as Louise Schumacher occupied only five minutes and two seconds of screen time, making it the shortest performance to win an Oscar (as of 2014), breaking Gloria Grahame's nine minutes and 32 seconds screen time record for The Bad and the Beautiful in 1953.[19]

The film's noted line "I'm as mad as hell, and I'm not going to take this anymore" and its derivatives are referenced in numerous films and other media, including Mad As Hell, a satirical Australian news show starring Shaun Micallef.[20] In Better Call Saul's first episode Uno, Saul Goodman quotes part of Jansen's eviscerating diatribe when he is lambasting the board of his former law firm, then tells his confused audience that his quote came from Network. The same camera angle is employed in both instances.[21]